Kissing another woman when Jessica Biel's not around is cool…as long as she's saving his life!

Justin Timberlake told sources at the Trouble With The Curve premiere that he may not have made it out of filming alive without Amy Adams' warm lips. The engaged actor explained:

"We shot that scene in the Blue Ridge Mountains and the water was just below fifty degrees. It was freezing … Amy actually saved my life. Unbeknownst to me, I was turning blue and couldn't process a thought, so she actually saved my life. I owe Amy Adams my life."

He was so cold that he actually needed mouth-to-mouth…or some smooching, as Adams joked:

"I saved his life; I did. Some people call it mouth-to-mouth, some people call it kissing–any way, it's nice work if you can get it."

Umm, yeah. It's VERY nice work!

We're sure the real reason they were exploring each other's mouths is because their characters fall in love while Adams helps Clint Eastwoodtalk to chairs scout potential baseball recruits.

U can find out if they had any on-screen chemistry this weekend when the drama hits theaters!